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Dust Collection, to cyclone or not to cyclone

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Forum topic by JonHitThingWithRock posted 12-02-2013 04:11 AM 2829 views 0 times favorited 16 replies Add to Favorites Watch
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JonHitThingWithRock

97 posts in 1181 days


12-02-2013 04:11 AM

OK, so I’m looking at upgrading my dust collection system (which currently consists of the harbor freight 1 hp model sitting on a piece of carpet and hose strewn about the garage haphazardly where they’re a constant tripping problem and source of loud profanity). I’ve narrowed it down to 2 grizzly models (I ruled out the 3+ hp models due to cost and the fact that i only ever have one tool going at a time, and i ruled out the smaller ones because I want really good suction). The first is the G0548ZP, which is a 2hp canister on top, plastic bag on bottom style for around $500 shipped.

The second one is the 1.5hp G0703, which is a two stage cyclone, that one’s around $900 shipped.

My dilemma is this: the cyclone collector has a much lower cfm rating than the canister style (775 for the cyclone, 1700 for the canister), all while costing $400 more. I realize that the cyclone has more features such as built-in remote turn-on thingy, but does the two-stage nature of the cyclone somehow nullify the massive cfm difference, or is it rated using some bizarre algorithm that only airflow nerds can comprehend? should i expect similar or better performance from the cyclone in spite of the cfm difference, or would i be better served getting the cannister-style. I can only assume the difference is down to the cyclone’s much smaller micron rating (0.2 vs the canister’s 1)

This will be going in a small shop without a lot of runs, probably one main trunk pipe, with branches going to various tools eventually, or possibly just the rockler dust right setup if I never work up the motivation to run pipes. Also, the canister-style is pre-wired for 220v, the cyclone is 120, but i would be buying the 220v conversion kit with it, so that’s not a factor. Thanks in advance for the responses.


16 replies so far

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lanwater

3111 posts in 2394 days


#1 posted 12-02-2013 05:36 AM

cyclone.

I had a JDS and transformed it into a cyclone. It is so much better now.
I still plan to change it a little more. I spent more money gradually changing and retrofitting than buying a new one.

-- Abbas, Castro Valley, CA

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JonHitThingWithRock

97 posts in 1181 days


#2 posted 12-02-2013 07:06 AM

I just realized that i can get a 3hp dual canister filter collector for a smidge over $700, rated at 2320 cfm, kinda tempting, still about $200 cheaper than the cyclone with half the horsepower and one third the suction, I need more convincing

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darthford

532 posts in 1383 days


#3 posted 12-02-2013 08:17 AM

I think you are getting too hung up on CFM ratings. I had a JDS single canister collector and was happy with it while I owned it. I filled many of those huge plastic bags full to the brim. The big canister did get clogged up fast and I had to turn the flapper frequently to knock the dust down into the bag. You have to ask yourself what the CFM is once the canister begins clogging.

I currently own the Grizzly cyclone above. The amount of material that makes it to the small plastic bag is nearly nothing. There’s a guy who’s been running a cyclone for 3 years and there’s only about 1 cup of material in his bag. The Grizzly moves a lot of air, its a beast for the price and an improvement over my JDS regardless of the CFM rating. But if you really want both the compact JDS 2HP cyclone about the same size as the Grizzly is rated 1700 CFM…its also double the price at $1,500. I had wanted to purchase the JDS over the Grizzly but the JDS was always out of stock, its a popular cyclone.

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Loren

8294 posts in 3107 days


#4 posted 12-02-2013 08:39 AM

Don’t bother with a cyclone unless it’s 3hp or more.

The thing you’re considering has an improved filter,
which is good because filters in cyclones are
the weak point.

I have a 1.5hp cyclone with a clog-prone filter and
a 3hp 4 bag standard dc. The main benefit of
the cyclone is its smaller footprint. It does an adequate
job on the table saw but the filter clogs when it is
used for planer shavings. I use the bad collector
for the planer now.

View Fred Hargis's profile

Fred Hargis

3926 posts in 1953 days


#5 posted 12-02-2013 01:00 PM

Cyclones have some advantages, but in the end what you want is maximum airflow followed by really good filtration to separate the debris from the air stream. the idea of a cyclone is to keep the debris from the filter, insuring you always have maximum air flow. But the design also allows the impeller to be engineered for air flow, without fear of being wacked by chunks of wood. Good thing, too. Cyclones introduce a huge amount of resistance to air flow, which why they often have larger motors/impellers to get the same CFM (most CFM ratings area joke, ignore them). It’s a lot easier to empty the dust bin as well, but back to the criteria: getting a large SS, with good filtration (1 micron or better) is going to work well. I agree with Loren, a cyclone with less than about 3 HP will be unsatisfactory (IMHO). Consider that 3 HP SS DC you pic’d…with that blower you could always build your own cyclone later. The only concern I would have with that unit is the footprint, looks pretty large.

-- Our village hasn't lost it's idiot, he was elected to congress.

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JonHitThingWithRock

97 posts in 1181 days


#6 posted 12-02-2013 04:51 PM

so i may be better off just waiting and saving until i can afford something like this 3hp unit

it’s a lot more expensive at $1750 with the stand and has an large footprint, I’m sure I’d have to clear out an entire corner from floor to ceiling, but i’m really looking to get the last dust collector I’ll ever need, am i overthinking all this? could i get by just fine with the single canister model and a super dust deputy on a trash can? oi, this dust collection thing is agonizing

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Fred Hargis

3926 posts in 1953 days


#7 posted 12-02-2013 05:08 PM

The problem with asking others about DC is the wide variety of opinions about what constitutes adequate DC. Some want to avoid sweeping the floors, others want to capture/contain every possible spec of dust. I lean toward the latter, and would suggest you get as much DC as possible, then put at least 6” ductwork in and run 6” as far as possible, modifying tools ports to accommodate it everywhere possible. Getting a powerful DC is wasted if you choke it down with undersized ducting. Other find that a smaller unit with 4” ducting is perfectly fine to meet their criteria. Only you know where you are on that continuum, so weigh the advice I and others offer with that in mind.

-- Our village hasn't lost it's idiot, he was elected to congress.

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Mainiac Matt

5989 posts in 1788 days


#8 posted 12-02-2013 05:50 PM

I have the G0548Z (green not white) and like it a lot. I did a review here.

I hemmed and hawed a lot about single stage vs. cyclones and ultimately went for the most cfm for the $ and decided I could add a Thein top hat on a trash can if it was an issue. But thankfully it hasn’t been, as the impellar on the G0548Z is very rugged and after two years in service, shows no dings or dents in it.

Cleaning the inside of the pleated filter was a bit of a chore, however, so I put a Thein plate in the mid section, which helps keep debris out of the upper section.

Cyclones are great, but you get more head loss pulling the air through them, so you need more HP and a bigger impellar to pull the same amount of air through a 2 stage as you do a single stage. If your read up on Bill Pentz’s site, he recommends that you draw in the fine dust (which is the stuff that’s really dangerous, as it gets into you lungs) and to do so you just have to move enough CFM…. upwards of 1,000

I’d jump on that dual canister if I had the space, and the $. But for my 425 s.f. shop, the G0548Z, along with a ceiling mounted Jet AFS-1000, have served me well.

-- Pine is fine, but Oak's no joke!

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JonHitThingWithRock

97 posts in 1181 days


#9 posted 12-02-2013 05:55 PM

Fred: I’m definitely leaning toward the removing every spec of dust camp, I’ve even planned out in my head how to get to the point of buying the 7.5hp cyclone that grizzly sells, but I have to bring myself back down to earth where I’m not rich, and don’t do this for a living and only use one tool at a time. I love the idea and concept behind cyclones, but the general consensus seems to be don’t go lower than 3hp, and I can basically understand the logic, but then the cheapskate in my head says “you got by with a 1hp harbor freight collector for a year, anything else would be an upgrade”. finding the balance is the goal, i suppose, and learning as much as I can from people with more experience and knowledge than me. I appreciate all the responses so far, and look forward to reading more perspectives.

View Shawn Masterson's profile

Shawn Masterson

1297 posts in 1408 days


#10 posted 12-03-2013 01:52 AM

I truly believe grizzlys figures are way over rated. if you compare the numbers how could grizzly possibly make more cfm with less HP. If I were to move into the $1500+ price range I would go with the Clearvue.

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crank49

3980 posts in 2430 days


#11 posted 12-03-2013 04:08 AM

CFM ratings are useless unless they specify CFM at a certain Pressure.
The useful data is usually represented on what is called a fan curve. A graphical representation of the fan’s capacity.

I marketing one machine might claim 1500 CFM without a pressure rating.
Another machine might be rated at 700CFM at 10” pressure.
And the fact is the 700 CFM at 10” might really be the more powerful of the two machines.

The disadvantage of a cyclone is that it uses some of your available pressure to create the vortex that does the work of separating dust from air.

The advantage of the cyclone is that it separates most of the dust from the air stream before it gets to the final filter. This means the filter is not going to get plugged up with dust as often.

Take two machines, one with a cyclone and filter and the other with just a filter, both with identical CFM and available pressure ratings and feed them both the same diet of dust and wood chips. In a few minutes the filter only unit will start to get plugged and its air flow will start to diminish. The cyclone and filter combo unit will continue to pull almost the same volume as when it was clean and new.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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HorizontalMike

7143 posts in 2373 days


#12 posted 12-03-2013 07:43 PM

Matt in post #8 = +10

I think Matt makes a good point about the increased head pressure(drag) with a cyclone. Personally, I think that a Thien Separator, be it the lid or the top-hat, will do the job with less head loss and thus will work better on smaller DCs. Just my 2-cents…

-- HorizontalMike -- "Woodpeckers understand..."

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JonHitThingWithRock

97 posts in 1181 days


#13 posted 12-03-2013 07:53 PM

I think I’m starting to lean more towards a smaller regular canister style dust collector for now, and adding a thein separator or super dust deputy later, thanks so much everyone for the advice and perspective.

View crank49's profile

crank49

3980 posts in 2430 days


#14 posted 12-03-2013 08:59 PM

If a Thein separator is designed and used properly there will be very little difference between the pressure loss of a cyclone and a Thein top hat separator.

Both devices depend on changing the velocity and direction of the air flow to strip out the dust from the air stream. Bottom line, more loss = more separation of dust.

It is even possible to achieve HEPA level of efficiency with just a cyclone and no filter, but it is not cost effective because pressure is much more expensive to create than volume.

Based on the affinity laws of air flows, often called just “the fan laws” as the speed of a fan is doubled the volume (CFM) is doubled, the pressure (inches WC) is squared (X4) and the power (HP) consumption is cubed (X8).

So, if you want to increase the pressure in a system without increasing the volume you can do this by making the fan impeller narrower and larger in diameter. But if you design the system to double the pressure and keep the same volume you will need 4 times the horsepower to run it.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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HorizontalMike

7143 posts in 2373 days


#15 posted 12-04-2013 12:22 PM

Crank,
My point is that the Thien separators are probably the best fit for small DCs (think HF) without overwhelming the smaller, less powerful, DC’s capacity. Sure, if money is of no concern, we could all have monster DCs with big cyclones attached, and in that case you would be correct.

I just think folks should NOT be tempted to “save $$$” on the DC only to turn around and “splurge $$$” on a cyclone to go with it. Such a plan of action leads to a mismatched DC system with the DC being overwhelmed by the demands of the cyclone. And yes, I understand that the Dust Deputy is designed for smaller DCs but at $200 it costs more than the HF DC itself. I do not find that combination to be an efficient use of our $$$. But then again, that is just my opinion.

BTW, I built my Thien “lid” separator for less than $50, including the 31gal.can.

-- HorizontalMike -- "Woodpeckers understand..."

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